Animal Fact Sheets

ORANGUTAN

(Pongo pygmaeus)

Classification and Range

Orangutans (oh-RANG-uh-tans) belong to the family Hominidae, which includes all four great apes: gorillas, chimpanzees, bonobos and orangutans. Distinct species of orangutans live on the islands of Borneo and Sumatra in Southeast Asia.

Reproduction

Females become sexually mature at around ages 7 or 8 and typically will only reproduce about 2 to 3 offspring in their lifetime. Males become sexually mature around the age of 13 to 15 years. Recently it has been discovered that sub-adult males, as well as adult male orangutans, have also successful been able to sire young.

Gestation period is about eight to nine months. Females usually bear single young; twins are rare. Average birth weight is 3.5 pounds (1.6 kg). In the wild, sexually mature females only give birth every 5 to 9 years, depending on the environmental conditions and food availability.

Life Cycle

Young orangutans are dependent on their mothers for survival during the first five years of their lives. Since young orangutans have few instinctive behaviors, they must learn from watching their mothers. Between 3 and 7 years, orangutans become increasingly independent, and leave their mothers by ages 5 to 8.

Rarely descending from trees, orangutans have nearly identical hook-shaped hands and feet that are well adapted for grasping and hanging from tree limbs. Young orangutans easily swing from limb to limb. Older, heavier adults must move through the forest slowly, using their hands and feet to test each branch to see if it will hold their weight. When required, however, an adult orangutan can move very fast. Orangutans have long, strong arms and relatively short legs, which is an excellent adaptation for locomoting from tree to tree.

Social Organization - The Solitary Life

Unlike gorillas, chimpanzees and bonobos who live in large male/female social groups, male orangutans are mostly solitary animals. Females may live in small groups composed of dependent young, other adult females and adolescents. The load-bearing limits of rain forest tree tops, combined with the scarcity of fruit, keep orangutans from living in large social groups.

During courtship and mating, however, adult male and female orangutans travel and forage together. The long call of a dominant male, audible for up to a mile (1.6 km), announces his presence to females who are ready to mate. The call also scares away other, less dominant males. Females seek out the male to breed, but after a few days they separate and return to their solitary life.

Location at the Zoo

Woodland Park Zoo's orangutan forest, located at the Trail of Vines exhibit in Tropical Asia, brings visitors eye-to-eye with orangutans in their treetop habitat. Visitors have an unobstructed view to observe orangutans as they may behave in the wild. The exhibit also has an indoor area for up-close viewing of the orangutans.

Conservation Connection

Orangutans are an endangered species. Overpopulation, logging, agriculture, conversion of forests to oil palm plantations, and other human activities are rapidly destroying forest environments required by orangutans for survival. While population densities are difficult to determine, estimates for the Bornean species are 54,000 while the critically endangered Sumatran species has dwindled to a mere 6,600 animals.

Woodland Park Zoo is involved in orangutan research and conservation in the wild. Zoo staff traveled throughout Indonesia doing tissue sampling of wild and captive orangutans. This study confirmed that the two orangutan subspecies are very different genetically, and should be managed separately and not allowed to interbreed. While the zoo's resident orangutans are hybrids (crossbred between Bornean and Sumatran species), and therefore are not allowed to reproduce, these animals play a critical role in educating zoo professionals and the public about the amazing orangutan. As an example, the first orangutan in vitro fertilization was accomplished at Woodland Park Zoo. Although no offspring resulted, it was an important step in the continuing development of embryo transfer techniques.

How You Can Help!

You can help preserve and protect wildlife and their habitat. Join and become active in Woodland Park Zoo and other conservation organizations of your choice. Please do not buy products made from wild animal parts.

Orangutan Taxonomy

Orangutan Fascinating Facts

An orangutan can make a mask of small branches to protect its face while raiding honey bee nests!

Each night orangutans build new sleeping nests high in the forest canopy. They even make a roof from broken branches to protect themselves from the rain!

Our Orangutans

TOWAN

Adult Male Orangutan

Born: February 1968, at Woodland Park Zoo. Twin of Chinta, father of Belawan and HeranHybrid: cross between Sumatran and Bornean speciesWeight: 270 pounds (122 kg)History: Raised in the nursery with gorillas; separated from gorillas in 1973 at age 5. Knows how to use tools such as a shovel, trash can, rake or wrench.Distinctive features: Largest of all the orangutans, housed with Belawan. Long hair, cheek pads, throat pouch, long calls

CHINTA

Adult Female Orangutan

Born: February 1968, at Woodland Park Zoo. Twin of Towan.Hybrid: cross between Sumatran and Bornean speciesWeight: 152 pounds (69 kg)History: Raised in nursery with gorillas; separated from gorillas in 1973 at age 5.Distinctive features: Medium build; has bangs. Hair falls forward on her forehead. Often seen on the ground. Prefers thickets, especially near waterfall.

MELATI

Adult Female 0rangutan

Born: December 1971, at the National Zoo (Washington, D.C.). Mother of Belawan and HeranHybrid: cross between Sumatran and Bornean speciesWeight: 166 pounds (75 kg)History: Received as infant from National Zoo. Melati is a twinDistinctive features: Medium build; only two fingers on her left hand due to an accident. Most visible, often seen in hammock nests outside or on one of the indoor platforms.